Consultant: Don't build a second Montlake Bridge

Published 12:23 am, Tuesday, September 11, 2012

A rendering of what a second bascule bridge would look like from Montlake Boulevard.

A rendering of what a second bascule bridge would look like from Montlake Boulevard.

Consultant: Don't build a second Montlake Bridge

1 / 1

Back to Gallery

Building a second drawbridge over the Montlake Cut may not be necessary to improve a messy interchange that can bog down traffic on the State Route 520 Bridge, a transportation expert told the Seattle City Council Monday.

As part of the new State Route 520 Bridge project, the state Transportation Department proposed building a second drawbridge parallel to the existing Montlake Bridge to provide more lanes for buses, bicyclists, and pedestrians, and to improve traffic/transit flow through the Montlake interchange.

But a consultant with Nelson/Nygaard, a transportation planning firm, said Monday that a second bridge might have such little effect on traffic that it would be a waste of money, and that more cost-effective options should be tried first.

"The bottom line is putting a second bridge in today would have a very low benefit for transit in terms of solving the transit reliability issues that occur in that corridor," said Tim Payne, who heads Seattle's office of Nelson/Nygaard Consulting Associates.

King County Metro operates 10 routes across the Montlake Bridge with seven routes coming from SR 520 and three operating locally through the Montlake corridor. Those routes serve 11,000 riders daily, connecting neighborhoods like the University District with the Central Area, Capitol Hill, and the Rainier Valley. But they're often behind schedule because they get stuck in traffic entering or exiting at the Montlake interchange. When the bridge has to open for boats, that adds to the delay.

But many residents hate the idea of a second bridge, and the City Council is wary, because it would require demolishing two homes and alter views of the current bridge, which is a historical landmark.

A workgroup made up of officials from the city, state and transit agencies set out to establish "triggers" for when a bridge would be necessary. Those triggers included conditions such as transit operations getting worse than 2011 levels, or when traffic backups on 520 reach more than 100 minutes daily as the result of Montlake Bridge openings.

Payne said Monday he doesn't think conditions will ever get that bad (prior to the start of tolling, the average delay on 520 due to Montlake bridge openings was about 32 minutes). Plus, a second bridge would only reduce those back-ups by about 5 percent. He said modest improvements should be tried first, such as queue jumps -- lanes that enable buses to bypass traffic at intersections - and automatic green lights for buses that run through the corridor.

The bridge also is a connection for bicyclists and pedestrians between the Lake Washington Loop and the Burke-Gilman Trail. When Sound Transit's light rail station opens outside Husky Stadium, that will draw more. But the sidewalks now are narrow, which creates bottlenecks.

Payne said the city had surprisingly scant data on pedestrian and bike volumes over the bridge. "It's important that we continue to monitor this corridor," he said. A congested bike lane with failing conditions for a three-month period also would be a trigger to build a new bridge, possibly even reserved for just bicyclists and pedestrians.

The state remains about $2 billion short of the 520 corridor project's $4.6 billion price tag A new floating bridge is under construction, but the westside segment from the Seattle shoreline to I-5 - including the Montlake interchange -- is unfunded.

Modifications to traffic lights and city streets as described Monday would cost in the thousands of dollars, while a bridge would be in the millions of dollars.

"After reviewing the technical details in the report, I' ve determined that it's unlikely a second bridge would deliver the benefits that would justify its costs and impacts on the neighborhood," Councilmember Richard Conlin said during a meeting of the special committee on the 520 project.

Conlin said he would direct council staff to prepare a resolution recommending the state hold off on a second bridge.

Payne said he'd recommend re-investing money for the second drawbridge into other parts of the project.

The question for the City Council is whether it could get the state to cover the tab on the less expensive alterations to city streets and traffic signals, if that meant improving 520 traffic.

"This will be helpful in meeting with legislators. "It's information we can use in discussion with them," said Councilmember Tom Rasmussen, transportation committee chair.